1. Field of the Invention
The invention relates generally to a release mechanism or coupling, and particularly to a release mechanism or coupling for automatically releasing parachute canopy riser straps from a parachute harness upon immersion in water. Other features of the invented release mechanism relate to a protective cover means for isolating sensing electrodes of an integral water-sensing electronic circuit from the external environment prior to deployment of the parachute canopy.
2. Description of the Prior Art
Objects are often parachuted from aircraft over large bodies of water. In addition, airmen are sometimes required to eject from a disabled aircraft over water and parachute to safety. Upon reaching the water, it is essential that the parachute canopy be separated from the object or airman. Specifically, strong winds, air currents and/or water currents can fill the parachute canopy and drag the object or pilot for substantial distances through the water, thereby increasing the difficulty of locating and picking up the object or rescuing the pilot. Also, where there are no surface winds or water currents, the parachute canopy may settle around the dropped object or pilot, and hamper recovery of the object or pilot. The canopy also hampers survival efforts of a pilot in the water.
Many different types of mechanisms are described in the prior art which automatically release parachute canopy riser straps from a parachute harness upon the object parachuted reaching the earth's surface.
For example, U.S. Pat. No. 3,306,653 issued to John A. Gaylord, describes a mechanical mechanism for releasing parachute canopy riser straps responsive to the decreased load on the mechanism when the object carried by the parachute strikes the ground or other surface. U.S. Pat. No. 3,624,674, also issued to John A. Gaylord, describes a webbing strap connector wherein an explosive squib, detonated by an external electrical circuit, energizes a mechanical release mechanism allowing the male and female members of the connector to separate. U.S. Pat. No. 3,624,813, again issued to John A. Gaylord, describes a break-away strap release for use on parachute harnesses, which is energized by an electrical explosive device detonated by an external electrical circuit.
In addition, there are many parachute strap release mechanisms described in the prior art which operate responsive to gas pressure from a remote source. (See U.S. Pats. Nos. 3,658,281; 3,744,102; 3,744,103; 3,767,143; and 3,766,611; all issued to John A. Gaylord.)
Finally, co-pending patent application, Ser. No. 467,298, entitled "An Electronic Water-Activated Parachute Release and Life Vest Inflator", assigned to the same assignee herein, describes a break-away webbing frame release mechanism adapted for automatic release upon immersion in water.
An analysis of prior art shows the preferred design objectives for an automatic parachute canopy release relate to (1) decreasing the probability of premature operation; (2) increasing structural resistance to mechanical shock and disfiguration; (3) decreasing the decoupling time; (4) decreasing energy required for disengagement; and (5) positive disengagement upon operation.